EGFR Targeting of Liposomal Doxorubicin Improves Recognition and Suppression of Non-Small Cell Lung Cancer

Abstract

Introduction

Despite improvements in chemotherapy and molecularly targeted therapies, the life expectancy of patients with advanced non-small cell lung cancer (NSCLC) remains less than 1 year. There is thus a major global need to advance new treatment strategies that are more effective for NSCLC. Drug delivery using liposomal particles has shown success at improving the biodistribution and bioavailability of chemotherapy. Nevertheless, liposomal drugs lack selectivity for the cancer cells and have a limited ability to penetrate the tumor site, which severely limits their therapeutic potential. Epidermal growth factor receptor (EGFR) is overexpressed in NSCLC tumors in about 80% of patients, thus representing a promising NSCLC-specific target for redirecting liposome-embedded chemotherapy to the tumor site.

Methods

Herein, we investigated the targeting of PEGylated liposomal doxorubicin (Caelyx), a powerful off-the-shelf antitumoral liposomal drug, to EGFR as a therapeutic strategy to improve the specific delivery and intratumoral accumulation of chemotherapy in NSCLC. EGFR-targeting of Caelyx was enabled through its complexing with a polyethylene glycol (PEG)/EGFR bispecific antibody fragment. Tumor targeting and therapeutic potency of our treatment approach were investigated in vitro using a panel of NSCLC cell lines and 3D tumoroid models, and in vivo in a cell line-derived tumor xenograft model.

Results

Combining Caelyx with our bispecific antibody generated uniform EGFR-targeted particles with improved binding and cytotoxic efficacy toward NSCLC cells. Effects were exclusive to cancer cells expressing EGFR, and increments in efficacy positively correlated with EGFR density on the cancer cell surface. The approach demonstrated increased penetration within 3D spheroids and was effective at targeting and suppressing the growth of NSCLC tumors in vivo while reducing drug delivery to the heart.

Conclusion

EGFR targeting represents a successful approach to enhance the selectivity and therapeutic potency of liposomal chemotherapy toward NSCLC.

Graphical Abstract

Keywords:

• targeted drug delivery
• bispecific antibodies
• PEGylated liposomal doxorubicin
• EGFR targeting
• non-small cell lung cancer

Abbreviations

BsAb, bispecific antibody; EC₅₀, 50% cell targeting concentration; Caelyx, PEGylated liposomal doxorubicin; EGFR, endothelial growth factor receptor; αEGFR, EGFR/PEG scFv BsAb; IC₅₀, half-maximal inhibitory concentration; IsoAb, isotype antibody; mAb, monoclonal antibody; NSCLC, non-small cell lung cancer; PBS, phosphate buffered saline; PEG, polyethylene glycol; scFv, single chain variable fragment.

Data Sharing Statement

All data generated or analyzed during this study are included in the article and its supplementary materials.

Ethics Approval and Informed Consent

All animal experimentation studies were conducted with approval from the Animal Care and Ethics Committee of UNSW Sydney (Sydney, Australia) and in compliance with the Australian code for the care and use of animals for scientific purposes.

Acknowledgments

This work was supported by the Children’s Cancer Institute (CCI), which is affiliated with the University of New South Wales (UNSW Sydney), and the Sydney Children’s Hospital Network. This work was also supported by an Australian Government Research Training Program (RTP) Scholarship and Royal Australian and New Zealand College of Radiologists. We acknowledge that elements of this research utilized services provided by the Queensland node of the National Biologics Facility (NBF) and the Australian National Fabrication Facility (ANFF) – Queensland node. NBF is supported by Therapeutic Innovation Australia and both facilities are supported by the Australian Government through the National Collaborative Research Infrastructure Strategy (NCRIS) program. We would like to thank the Katharina Gaus Light Microscopy Facility at Mark Wainwright Analytical Centre (UNSW) and for their support and resources involved in this work; and UNSW Sydney for Research Infrastructure Support to establish the Liposomal Development lab at CCI.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

Professor Kristofer Thurecht reports the bispecific antibody technology has been awarded patent number WWO2016123675A1. The authors declare that they have no other competing interests in this work.

Additional information

Funding

This work was funded in part from the Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology (CE140100036, to M.K. and K.J.T.); ARC Training Centre for Innovation in Biomedical Imaging Technologies (IC170100035, to K.J.T.); National Health and Medical Research Council Investigator Grant (#2016464 to MK) and a Tour de Cure Grant (to MK). K.J.T. acknowledges the award of a Career Development Fellowship (APP1148582).